Acoustic detonation suppression and spark plug mounting device for internal combustion engines



March 27, 1956 o JR 2,739,583

ACOUSTIC DEITONATION SUPPRESSION AND SPARK PLUG MOUNTING DEVICE FORINTERNAL. COMBUSTION ENGINES Original Filed July 2, 1951 2 Sheets-Sheet1 FIG. I

FIG.2 28

INVENTOR. ALBERT G. BODINE JR.

A TORNE Y March 27, 1956 BODWE, ]R 2,739,583

ACOUSTIC DETONATION SUPPRESSION AND SPARK PLUG MOUNTING DEVICE FORINTERNAL COMBUSTION ENGINES Original Filed July 2, 1951 2 Sheets-Sheet 2FIGS 7 FIG.7

INVENTOR.

ALBERT G. BODINE JR.

A TTORNE Y United States Patcnt O A OUSTIC DETONATION SUPPRESSION ANDSPARK PLUG MOUNTING DEVICE FOR IN TERNAL COMBUSTION ENGINES Albert G.Bodine, Jr., Van Nuys, Calif.

lication October 24, 1951, Serial No. 252,818, which a division ofapplication Serial No. 234,688, July 2,

1951, now Patent No. 2,573,536, dated October 30,

1951. Divided and this application December 6, 1955, Serial No. 551,261

3 Claims. (Cl. 123-l91) This invention relates generally to internalcombustion engines and to means for suppressing irregular burning anddetonation of fuel-air mixture therein. The invent on is based on mydiscovery that detonation in COlTlbLlSilOl'l engines involves acousticphenomena and can be alleviated by means of certain acoustic apparatusused in combination with t'ne combustion chamber.

The present application is a division of my copendlng application SerialNo. 252,8l8, filed October 24, 1951, entitled Engine Detonation Controlby Acoustic Methods and Apparatus, which was a division or my earlierappli cation Serial No. 234,688, filed July 2, 1951, entitled EngineDetonation Control by Acoustic Methods and Apparatus (now Patent No.2,573,536), which last-mentioned case was in turn a continuation-in-partof my prior parent application Serial No. 24,744, filed May 3, l94 8,entitled Acoustic Means for Suppressing Detonation ll'l internalCombustion Engines. now abandoned.

The present invention is based on the fact that detonation in an enginecombustion chamber produces sound waves, a large part of which are athigh amplitude at resonant frequencies of the chamber, and On mydiscover that the sound waves produce the various well-known and harmfulmanifestations of detonation. According to my basic invention, 1 inhibitor attenuate these harmful eifects by interfering with or attenuatingthe high amplitude detonation-induced sound waves, and this is done byuse in connection with the combustion chamber of acoustic attenuationmeans made responsive to the frequencies at which detonation inducedsound waves appear at high amplitudes.

One type of acoustic attenuation means disclosed in my a'r'ore-mentionedearlier applications, with which the present application is connected bycopendency, comprised a plug-in device adapted to be screwed into a partformed in a wall of the combustion chamber. The present invention isdirected to a specific form of attenuator of this general character,including means for mounting a spark plug.

An object of the invention is the provision or an especially effectivedetonation controlling sound wave attenuator of a type capable of beingscrewed or plugged into a suitable port formed in a wall of thecombustion chamber, such as the spark plug port with which the chamberis already equipped.

A further object is the provision of an acoustic sound wave attenuatorcapable of being plugged into the spark plug port of the combustionchamber wall and equipped with means for supporting the spark plug.

in my earlier aforementioned applications, detonation sound waveattenuators were described of a type involving porous absorbers as wellas Helmholtz resonator forms embodying generally the concept of aHelmholtz resonator cavity with a porous plug or wall across theeffective neck of the cavity. The basic theory and operation of saidattenuators is fully set forth in said earlier applications,particularly in Patent No. 2,573,536.

2,739,583 Patented Mar. 27, 1956 ice An illustrative embodiment of theinvention is shown in the drawing, which is a vertical medial sectionthrough an engine cylinder, cylinder head and piston.

The engine shown in the drawings is of the valve-inhead type, having awater-cooled block 10, water-cooled head 11, and piston 12 Working in acylinder 13 within block 10. Head 11 comprises a generally domed orhemispherical chamber wall 14 defining a combustion chamber 15 overpiston 12. In the center of head wall 14 is a threaded port 16 which maybe of a size and type to receive the conventional spark plug, but intowhich the attenuator 17 of the present invention is installed, the sparkplug 18 being carried by the attenuator.

Continuing with the description of the illustrative engine, intake andexhaust valves will be understood to open to combustion chamber 15through wall 14, an exhaust valve 19 being shown, and it beingunderstood that an intake valve (not shown) will be locatedsymmetrically with respect to the exhaust valve, forwardly of the planeof the drawing.

Referring again to the attenuator 17, the same incorporates or hasprovision for mounting spark plug 18, as earlier mentioned, 30 that thedevice in this form may be used with conventional engines by simplyscrewing it into the spark plug port. Thus, into port 16 is screwed theexternally threaded tubular stem 25 of a cylindrical porous body 26, thelatter having cylindrical interior cavity 27, whose upper end isinternally screw threaded to receive conventional spark plug 18. Thebody 26 is here shown to be enclosed within a metal closure shell 28,and is preferably formed, inside said shell, with an externalcircumferential channel 29 providing a Helmholtz resonator cavity space.It will be seen that l have thus interposed a porous body between theengine and the spark plug, the device serving as a spark plug adapter.The combustion chamber space immediately adjacent the spark plug is acommon origin point for radial wave forms of detonation disturbance inengines like that shown in Fig. l, and by having this space immediateiyadjacent porous wall 26, the destructive detonation sound waves arematerially absorbed in an area near their source. By employing theoptional but preferred Helmholtz resonator cavity space 29, the deviceis made more frequency selective, and by choice of proper designconstants for frequency response, depending upon the volume and shape ofthe combustion chamber in any given case, the particular detonationfrequency desired to be combated is thereby selectively attenuated. Anobvious optional arrangement is to form the stem 25 of solid material,for mechanical strength, and form the balance of the memher as of.porous material. Various materials are suitable for the porous body, forexample, sintered powdered metal. Suitable porous materials and methodsof fabrication, as well as the specific etfect of the porous materialson detonation, were disclosed fully in Patent No. 2,573,536, and neednot be here repeated.

It will be understood that the drawings and description are merelyillustrative of one specific embodiment of the invention, and thatvarious changes in design, structure and arrangement may be made withoutdeparting from the spirit and scope of the appended claims.

I claim:

1. Detonation suppression means for an internal combustion engine havinga combustion chamber, formed with a threaded port; a hollow porous bodyhaving a hollow, externally screw-threaded stem adapted to be screwedinto said threaded port, said hollow body opening into said combustionchamber through said stern, said body having a multiplicity of fluidpassageways of substantially capillary dimensions opening into itshollow interior.

2. Detonation suppression means for an internal combustion engine havinga combustion chamber, formed with a threaded port; a hollow porous bodyhaving a hollow, externally screw-threaded stem adapted to be screwedinto said threaded port, said hollow body opening into said combustionchamber through said stem, said body having a multiplicity of fiuidpassageways of substantially capillary dimensions extending between anexterior surface of said body and the hollow interior thereof, and wallmeans enclosing a resonator cavity adjacent said exterior surface.

3. Detonation suppression means for an internal combustion engine havinga combustion chamber, formed with a threaded port; a hollow porous bodyhaving a hollow, externally screw-threaded stem adapted to be screwed 4into said threaded port, said hollow body opening into said combustionchamber through said stem, said body having a multiplicity of fluidpassageways of substantially capillary dimensions opening into itshollow interior, and said body having also a threaded spark plug portopening into its said hollow interior.

References Cited in the file of this patent UNITED STATES PATENTS1,116,364 Baker Nov. 10, 1914 1,466,432 Gerleman Aug. 28, 1923 1,490,849Philip Apr. 15, 1924

